Thursday, January 20, 2011

You Gotta Measure if You're Gonna Save

Reading all the literature on "saving energy", you begin to recognize a pattern. First off, everyone with energy saving advice expects you are reading their words because your own house sucks for energy conservation, and you want some way to cut down on energy consumption and save money. And they are just the people to do it. That may, or may not be true of you if you are reading this column. (I know for a fact it's not true of me, but we aren't here to talk about me.)

The advice itself isn't stupid or terrible or wrong. All of us have a "green obligation" to make sure our homes are as energy efficient as possible. But it can be short-sighted. It can be less true for you than it is for someone else. Reading these words over and over again (usually on the internet), you begin to recognize a familiar pattern of "safe" advice that sounds smart and gives the writer an air of authority, the illusion that they know what the hell they are talking about. The writer has to collect a paycheck from someone, so the writer tries to apply to as many of their readers as possible. It's advice that may or may not apply to you. The points tend to run this way:

1) Replace incandescent bulbs with CFL bulbs.
2) Change HVAC filters.
3) Caulk (in various ways, various places)
4) Turn down the thermostat on your space heat.
5) Turn down the thermostat on your water heater.
6) Put "vampire loads" on outlet strips and switch them off at night.
7) Install water saving shower heads.
8) Insulate hot water pipes.
9) Open or close crawlspace vents (as appropriate)
10) Replace outdoor floodlights with automatic sensor lights. Make those lights CFL too.

Some of the more adventurous conservation advocates will even go to the point of recommending:
11) Install a programmable thermostat.
12) Install storm windows.
13) Install storm doors.
14) Add insulation to your attic or crawlspace.

Some of these things are a hell of a lot of work. Some of these things might require hiring a professional and cost a lot of money. And some of these things just might not work worth a damn.


What Are You Saying?

Now don't get me wrong: I'm not saying "don't do these things". Do them - wholeheartedly and happily, especially if you haven't. I'll even go further and say do them without a particular dollar value of savings in mind. Why? Because all of these things generate payback. Even if you save, say, a dollar a month off your electric bill, that's a real, actual, after-tax $1.30 directly back into your pocket, every month, forever. (Well, at least until you kick the bucket, but that's another story.)

Do them if you are uncomfortable in your own home - if you freeze in the winter or burn up in the summer or if the lighting is bad or there's no airflow or if you'd just like to have a fancy thermostat. Do them if you are mad about the check you write every month and want to see some money back, even if it's a small amount. It's OK to do something if you simply WANT to.

But don't do them just because Mr. Green Advisor said to, or because you feel guilty about not being green or not saving energy. If, for you, you want to make a big impact, or save a lot of money, or really make strides and "be green", or most importantly, you are thinking about adding solar hot water, solar electric or wind power sources to your home, then keep reading.


An Exercise In Estimation

Let's estimate, using nameplate ratings, what switching over to CFL's can save you on one monthly bill.

Say you've got one of those light bars in your bathroom. It holds four incandescent "bombe" bulbs. It's the light fixture builders and interior designers pushed on all of us for the last 20 years saying "it gives the right color balance" for the morning visit to the bathroom or applying makeup.

You go out and buy a four-pack of CFL's that will nicely and attractively replace the four incandescents in your bathroom light bar. The plan is to replace four 60watt incandescents with four 14 watt CFL's. Then sit back and watch the money roll back in!

You run your bathroom light bar for two hours a day. 1 hour in the morning getting ready for work, and 1 hour at night getting ready for bed. That's approximately 60 hours per billing month on your bill.

4 x 60W = 240W - original power draw with 60W incandescents
4 x 14W = 56W - new power draw with CFL's.

You were paying:

240W instantaneous power draw, or .240KWH for each hour you use the light bar
2 hours x 30 days/month x .240KWH = 14.4 KWH power cost on each bill

If you pay 14 cents/KWH, that costs:
.14 dollar x 14.4 KWH = $2.016 per bill


The CFL's Use:

56W or .056KWH for each hour
2 hours x 30 days/month x .056KWH = 3.386KWH power cost on each bill
If you pay 14 cents/KWH, that costs:
.14 dollar x 3.386 = $0.47, or 47 cents.

You've saved:
184W instantaneous power draw, or .184KWH each hour you use the light bar
2 hours x 30 days/month x .184KWH = 11.4 KWH lowered on each bill

If you pay 14 cents/KWH, that saves you:
.14 dollar x 11.4KWH = $1.54 per bill

(and we know our calculations are good: if you just subtract the original cost from the final cost, you still get $1.54 per bill)




Reasons NOT To Use CFL's

There are subtleties to the notion of replacing your incandescent bulbs with CFL's that bear some mention.


The light output of ALL bulbs - incandescent or CFL - falls slightly - by 5-10% over the life of the bulb, and for all bulbs, there are potential changes in their electrical behavior over their life span.

CFL's also have the characteristic that they put electrical "noise" back on the power line. This can have all kinds of strange effects - for example, X10 modules won't properly control CFL's and won't consistently turn them off or on due to the electrical noise they emit. Wi-Fi network signals may be interfered with.

The light output spectrum of CFL's is different than incandescent bulbs. Some argue that the light output is of much lower quality and harder to read by. But CFL manufacturers  have responded by making devices that output light in 6000K, (daylight) 4200K (bright white) and 3500K (soft white) color temperatures.

And yes, there is the concept of "embodied energy", where, if it takes much more energy to make a complicated CFL than a simple incandescent, then your net "green savings" may not have been achieved.

These are all fair criticisms of CFL's. If they bother you bad enough, or if the light output and quality are not to your liking, then don't switch to CFL's. Wait around another couple years, we'll have LED light output devices that have far, far less embodied energy, more stable wideband light output, far less deterioration over time, generate even less heat, and more importantly, use even much less more light than CFL's.

To give you a quick update on how much savings, the CFL's used in the example above draw 14W each, total 56W for the light bar. LED lamps will drop that down to 3-5W per bulb, so worst case, those LED lamps will use 20W total for the entire light bar vs. 56W for the CFL's. That's a 220W instantaneous savings for a monthly electric bill savings of $1.84. And the potential lifespan of an LED product can extend well beyond 100 years of "on time". A well engineered LED bulb could be the last bulb you ever buy in your entire lifetime for the fixture where you use it!


Not Bad, But I Expected Much More.

I hope the quick calculations have demonstrated that it is worthwhile to make changes around your home to save energy and become "more green". Good CFL's these days will last 10 years and are going for around $6/four pack, so for your $6 investment, you'll get that $1.54 back consistently on every electric bill, 12 times a year for 10 years, or 120 x $1.54 = $184 over the 10 year life of the bulb.

But even if you have a very efficient home - maybe even energy star - you're paying $150-$300/month for the various forms of power you use, and $1.54 per bill just ain't cutting it. Even the very optimistic 10 bucks per month won't even buy you and your loved one a cheeseburger meal for that night out to celebrate the savings.

So, you do some (or maybe even all - wow!) of these things. You might be more comfortable in your home, but the hoped-for percentage of savings on your electric/gas bill just doesn't materialize. You might make a dent, but nothing comparable to what you expected, and worse yet, you've spent all this money and just aren't getting the return you wanted to see - an extra $10/month just wasn't worth it.

What went wrong? Why didn't you save that "ton of money" you expected? Why didn't you make the savings predicted by the person who wrote the column?!? Where's that great payback for all the effort?

The problem is really one of first knowing what the problem is, then solving that problem. The dudes giving advice know nothing about your home or living style. No one would expect them to. But there's much art to the science of saving energy, and that's something they cannot advise you on. You have to find out for yourself.


So What's The Point?

The point of this blog isn't to sell you on the idea of doing a laundry list of changes around your home. If you live in a really crappy house in Minnesota and you're freezing yourself all winter long, you have plenty other reasons to work on your energy savings - namely so you can enjoy living in your home and not freezing your ass off. Surely you've done most of these things by now just to get control over a runaway electric or gas bill, and to be more comfortable.

The calculation above is an estimate that attempts to understand how much YOU use the light bulbs in question. You might take quick showers and spend only 30 minutes in the bathroom, or you might take long luxurious showers and spend more than that two hours daily.

The nameplate ratings of the bulbs were real - I took those right off the package, and are accurate even if they do change ever so slightly over the life of the product.

The point is that we don't even get off the dime with "being green" and saving energy without a very, very good understanding what we do and how we behave in our homes, our cars, our offices. 

And if you ARE sitting in your house in Minnesota, suffering for the six or seven months of winter every year, then you know damn well you've got to do something, and replacing four CFL's in your bathroom just isn't going to cut it.


We Buy Power After We Use It

Imagine, if you went grocery shopping, and everything you bought was in black, unlabeled boxes that you can't see, tough, measure or even weigh. You believe you are buying the right food you need, but really, you have no clue how much is in the box. You go to the checkout, scan everything, pay the bill and walk out with your new purchases. Then you get home and find out you've bought 50 lbs of dog food and you don't own a dog.

That's the way we buy power every month. When the power bill comes, most of us don't have a damn clue how much we've used or why we write the check we do.

Usually the person writing the check freaks out when they write the check, and if they are a real asshole about it, they'll blame someone in the family they know has left a light on, the fridge open or a space heater running.  The fact is, they don't really know why they are writing the check, they just know it hurts like hell and they've got to say something to somebody.

You may or may not have done the advice column things I listed at the beginning. You may be living in an apartment and have no more than, say, 10 bulbs in the whole apartment. You may be in a 5000 square foot home and replaced every damn bulb in the house and still not seeing jack for savings on your power bill.

If you are buying those black boxes every month and writing a fat check and you're pissed off and just can't take it any more, keep reading.



The Next Level: A Basic Rule of Thumb

First, I'm not saying DON'T do the advice columnist stuff. Do it, if for no other reason than to simply become more familiar with how your house is working and to get more comfortable. Use the information you can get from your five senses: if you are cold when you sit near a window, fix it, caulk it or install a storm window. If you can scald yourself in the shower or you find yourself replacing hot water heater elements, find out how to dial back your water heater or pay someone to come in and do it for you.

To go beyond the "green advice columnist", to make a real and lasting impact on your energy usage and your comfort, you have got to figure out, for your particular situation, what your mix of electrical (or gas) loads are in the house, so you will know where your effort can best be put to use. You have to open the black boxes and see what's inside. To do that, you have to get a good ballpark understanding of what your usage is, then refine that ballpark understanding by measuring how much energy your house and all the appliances within are consuming.

People who make conservation their business will tell you that for an all-electric home, electrical loads are roughly distributed three ways:

1/3rd goes to HVAC
1/3rd goes to heating water
1/3rd goes to "plug loads" - anything you can plug into an outlet in the home. This includes things like the oven or dishwasher as well.

If you use gas for hot water heat, cooking or space heating, the numbers are the same on an energy basis, but may not split this way according to cost. Nevertheless, the idea holds: general understanding of what you use in energy every month.

So what? So freaking, fracking, faulking what?

If you take the average of your power bill over an entire year, and say, it's $300, then in a typical home with nothing broken and the HVAC working normally, you're spending $100 a month to heat/cool the house, $100 a month making hot water, and $100 for everything you plug into electrical outlets.

So What, is that this is a first step toward opening the black boxes. We're talking about energy here. At the point of metering, where you are getting billed, you can't see it, smell it, taste it or touch it.

Well, you can, but that wouldn't help you and it would likely kill you. So we have to go at this backward. We start with the rule of thumb, then work our way toward a better understanding, over time, of how we individually vary from this overall rule of thumb.

Along the way, we'll figure out how much energy we really can SAVE through conservation. Then we'll go further, and figure out where we can apply solar (PV or hot water) or wind energy to make an even bigger impact.

Getting Green With It All....

I live in an all-electric powered home in the southeast US. It's a relatively recently built, well designed and energy efficient home. In November 2009, we had a problem with our heat pump - it would not hold refrigerant - and it was traced to a factory defect in the "A-coil", which is the part of the heat pump that transfers heat to-or-from the interior air, being blown over the A-coil.

The local firm that installed the heat pump then replaced the A-coil. Remember, this was early November, 2009, beginning of the winter "heating season" here in the US. As a result of installing the new A-coil, the firm made mistakes that compounded themselves over the next three months. In the meantime, we had a very cold January, and the problems they caused with the heat pump developed a situation where the "emergency heat strips" were the only means of heating we had - the heat pump itself would not, well, "pump heat".

Dealing with the vendor was one bad problem, but then we got the power bill the next month for the runaway power consumption of the unit - and it was about $120 higher than normal for that time of year, even for an exceptionally cold January. The impact of the charge was significant, on top of the hundreds of dollars spent with the vendor. The sting of it all was that I had no clue the heat strips were coming on continuously until I got the bill.

Being an electrical engineer for all of my adult life, this was an unacceptable situation. Not understanding the power draw of all the circuits in my house was the key to recognizing the problem in the first place. Also realizing that with every passing day, I was losing data essential to gaining that understanding, I was willing to go out and buy something I could simply and quickly attach so I might monitor my whole-house power consumption.

With all the talk about "going green" and "reducing your carbon footprint", knowing how much energy you use in your home would be a vital, fundamental step toward saving energy, money and carbon. I expected to find at least a dozen different devices that could measure electric power draw by a home, a full range of products at all different kinds of prices.


What I found on the internet was really only two viable products: "TED 5000" (The Energy Detective) and something called "eMonitor" from Powerhouse Dynamics. The TED 5000 fit the bill for a rapid whole-house solution at about $300. Not too bad. But the eMonitor, now that was the ticket: whole house, all-circuit monitoring. It looked mature, well-made and highly capable. But to implement the eMonitor product at my home, I'd have to buy two of them, a "larger" and "smaller" version of each, to install on both breaker boxes here at the house. Total would come out to roughly $2000. And to make matters worse, when you buy the eMonitor, you send your data to them, and they keep your data in their "cloud". The initial price of the unit includes a two-year "subscription". After that, you've got to pay an annual fee to keep the power measurement goodness running.

That was enough to completely end the idea for me. I'm not interested in putting my data in your cloud and paying for it, thank you very much. I want to keep my own data so I can improve the user interface, add features when I'd like, and fine-tune the sensitivity of the unit to match the power draws of the circuits in the house.

So, the quest begins: to design, build and implement, first a whole-house power monitoring solution, then from there, move on to a whole-house power monitoring system that can track energy usage on all circuits. And to do it for well under $2000.

Follow along with me as I research the problem itself, the components needed to do the measurement, and develop a solution that takes the measurement and brings that data all the way to your computer screen, where you can look, learn, and act.